Rosneft will acquire a 19.6% stake in SeverEnergia by purchasing Enel's 40% stake in a joint venture with Eni S.p.A. Gazprom Neft, the oil arm of state gas firm OAO Gazprom, holds 51% of SeverEnergia, which holds licenses on the Yamal peninsula in Russia's Arctic.

Rosneft says it wants to become a major player in the Russian gas business, which is currently dominated by Gazprom. The government is drafting legislation to end Gazprom's monopoly on gas exports by allowing other producers, including Rosneft, to ship liquefied natural gas.

Rosneft and other producers, such as OAO Novatek, have been eating into Gazprom's domestic market share by snapping up contracts with large industrial consumers.